Estimating method of retaining pile and surface deformation of loess pile-supported foundation pit#br#
WANG Xiaoyong1, 2*, ZHENG Jianguo1, 3, YU Yongtang2, MAO Jidong4, ZHANG Zhiyi2, YANG Lei2, LIANG Yi2
(1. College of Civil Engineering, Xi?an University of Architecture and Technology, Xi?an, Shaanxi 710055, China; 2. China United Northwest Institute for Engineering Design and Research Co., Ltd., Xi?an, Shaanxi 710077, China; 3. China Jikan Research
Institute of Engineering Investigations and Design, Co., Ltd., Xi?an, Shaanxi 710021, China; 4. Shaanxi Construction
Engineering Group Co., Ltd., Xi?an, Shaanxi 710003, China)
Abstract:This study addresses the critical challenge of accurately predicting retaining pile deformation and ground surface settlement of pile-braced foundation pits located in loess areas. Based on the data collected from 19 projects in Xi?an, the horizontal deformation of retaining piles and the ground surface settlement were systematically analyzed. By comparing the deformation characteristics of foundation pits in loess and soft clay, a modified Gaussian curve and a skewed distribution curve were proposed to better characterize the settlement profiles. By systematically integrating the effects of pile insertion ratio, the piles? flexural rigidity, and the bracing stiffness, a comprehensive stiffness coefficient for the entire support structure was established. The findings reveal that the pile deformation exhibits a concave profile, with the maximum displacement located at the depth of 0.55–0.75 times the depth of the foundation pit (H). Horizontal deformation diminishes and approaches zero beyond a depth of 1.5H. The maximum ground surface settlement is observed at a distance of 0.5H from the pit?s edge, with the zone of influence extending to approximately 2H. Compared with traditional methods, the comprehensive stiffness coefficient proposed in this paper significantly enhances the accuracy of pile displacement prediction, which improves the fitting determination coefficient by 1.5 times. These findings offer valuable insights for optimizing the design and safety assessment of pile-braced foundation pits in loess areas.
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